Driving mechanism



H. R.'DAViES.

DRIVING MECHANISIVI.

APPLIc/IIIQII IIIED IIILY22, I9I8.

1,330,848. Patented Feb. l?, 1920.

sleeve was fixed immovably upon the internal sleeve 3, the rapid rotation of the shaft would be transmitted with full force to the pinion 7 when it came into Contact with the .outer sleeve 10, the result of which would be a stripping of the gears and other possible destructive effects. Because, however, of the employment of the spring on the internal sleeve, the sleeve 10 gradually gives under compression incident to the contact of the pinion against its inner edge, so that the transition of the pinion from zero rotation to motor shaft rotation is effected gradually without any serious destructive results.

When the pinion is in contact with the external sleeve and is exerting force thereupon, it is at once evident that there is a tendency to force the internal sleeve inwardly along the shaft, and as the engagement between the sleeve and the shaft permits of' a limited movement, the sleeve moves inwardly to a certain extent, limited by the length of the slot 16 in the sleeve. There is thus provided a dual motion of contacting parts when the pinion is in initial engagement with the outer sleeve, so that a fiexible and resilient relationship is thereby secured.

The object of utilizing a longitudinal inter-action between the motor shaft and sleeve 3 is two-fold. As is well-known in internal combustion engines, resistance oered to rotation of the crank shaft, varies with the point of compression in the various cylinders, so that there is a lack of uniformity in the re-active force of the engine. As this change of re-active force is very rapid, and inasmuch as the pitch of the screw thread upon which the'pinion rides is comparatively high, movement of the pinion is not sufliciently rapid to take care of this varying force. Relative motion of shaft and inner sleeve is, however, instantaneous along the slot 16, which easily takes care of this rapid pressure variation.

A second advantage of the slot connection between the shaft and sleeve, is apparent -When one considers the effect of the nonenmeshment of the pinion with the fly-Wheel gear. If the pinion in traveling outwardly,` should engage the gear in such a way that enmeshm'ent was impossible, destructive effects very likely would ensue, unless some means was provided to relieve the jam of the pinion and permit its proper enmeshment. In my device, when the pinion lcomes in proper contact with the gear-teeth of the fly-wheel, the sleeve 3 immediately begins to move inwardly, the pin 17 traveling along the slot in the sleeve. This movement relieves the pressure intermediatey the pinion and gear,'and permits a slight rotation of the pinion in the direction of rotation of the motor shaft, which carries the pinion over the point of jam, and permits it, under pressure, to slide into proper position on the ear.

When the engine starts up under its own power, inasmuch as the speed of rotation of the crank shaft greatly exceeds that of the motor shaft, the pinion 7 is moved inwardly along the sleeve and out of mesh with the gear, it being assisted in this action by the spring.

From the above description, it is evident that I have provided a simple and effective driving mechanism which is entirely auto.

matic in its operation, and which takes care of variations in compression in engine thereof, and, therefore, I desire to claim' the same broadly as well as specifically, as indicated by the appended claims.

Having thus described my invention,

what I claim as new and desire to secure by Letters Patent, is

1. In a screw gear, the combination of.

an engine gear; a motor shaft; la sleeve having a threaded portion mounted on said shaft, and adapted to have longitudinal movement relative thereto;t an internallyA threaded pinion mounted on the threaded portion of said sleeve, adapted to have longitudinal movement relative to said sleeve and said shaft into and out of ymesh with said engine gear; a second sleeve loosely mounted on, and having movement relative to said first named sleeve; an out-turned' flange on. one end of said second named sleeve, the opposite end thereof being adapted t0 be engaged by said pinion; an ouf-turned {ia-nge at one end of the first named sleeve; a compression spring coiled on said first named sleeve, intermediate said anges; casing inclosing said spring, having an iii-.turned end flange adapted to limit movement of the liange of said second sleeve; and means for attaching the casing to the end of the shaft.

. .2. In a drive mechanismI for 'internal combustion en lines, ythe combination of-an internal com. ustion engine; a gear connected with said engine; a starter shaft; a sleeve for said shaft having an out-turned end fiange, and a threaded portion; connections between said sleeve and shaft permitting longitudinal movement therebetween; an in ternally threaded pinion having. screwthwaded engagement with the threaded portion of said sleeve, and adapted to have longitudinal movement into mesh with said gear; a second sleeve on said rst named sleeve, havin an out-turned flange, the opposite end o said sleeve being adapted 'to .sbeengaged by lsaid pinion; a compression spring coiled Ourthe First named sleeve, in-

tel-mediate the flanges of the sleeves; a cas# ing inoloslng the spr1ng;'hav1ng an end plate 'adapted to limit movement of the s ecf ond named sleeve; and means for attaching the casing to the lstarter shaft. A i In a drive mechanism for internal'combnstion engines; the combinationv of'an 1nternal combustion engine; a gear connectedA` to the' engine; a starter shaft; a sleeve on said shaft, having limited axial movement relative to the shaft andv rotary movement therewith; a second sleeve on said first named sleeve, having limited axial movement relative to the lirst named sleeve; means for yieldingly holding both sleeves at one limit of theiraxial movement; and apinion threaded onsaid first named sleeve and adapted to mesh with the gear, said pinion engaging said second sleeve asr it moves into mesh withl the gear.v

4. In a drive mechanism for internal comsingle means for ,yieldingly holding both sleeves at one limit of their axial movement, and a pinion threaded on said first sleeve and adapted to inesli with said gear and having yielding engagement with said second named sleeve.

lIn testimony whereof, I afiix my signature.

HENRY R. Davies. 

